1. Field of the Invention
The present disclosure relates to a light-emitting element.
2. Description of Related Art
In recent years, backlight units for liquid crystal display devices are required to be thin. Also, edge-emission type light-emitting elements, which are light sources for the backlight units, are strongly required to be small and/or thin. Further, in addition to the reduction in size and thickness, light extraction efficiency of the light emitting elements is strongly desired to be high. For this purpose, a light-emitting element in which a recess is formed in the lateral surface of a semiconductor layered structure has been proposed (for example, see Japanese Unexamined Patent Application Publication No. 1995-202263). Also, in place of utilizing light emitted from the upper surface of the light-emitting element, utilization of light emitting from the lateral surface of the light-emitting element has been proposed (for example, see Japanese Unexamined Patent Application Publication No. 2006-245380).
However, for some specific uses, the light-emitting elements in which directivity with respect to the specific directions is further increased without using optical members such as lenses, in addition to having further high light extracting efficiency. For example, in the case of using a light guide plate in the backlight unit for the liquid crystal display device and the light sources are arranged on the lateral surface of the light guide plate, it is preferable that the liquid crystal display device have a narrow frame, and it is preferable that the number of light-emitting elements be small so as to reduce the cost of the light sources. For these uses, it is desirable to omit the optical members such as lenses in the backlight unit, and the light-emitting elements having such light distribution characteristics that allows good coupling efficiency between the light from the light-emitting elements and the light guiding plate is required.
It is an object of the present invention to provide a light-emitting element that achieves a high light extraction efficiency and control of directivity.